Adjustable belt



FIG. 1 is a front perspective view of an adjustable belt showing my new design;

FIG. 2 is a front perspective view thereof with the adjustable structure disconnected;

FIG. 3 is a rear perspective view of FIG. 1; and,

FIG. 4 is a fragmentary view of the left side of the belt of FIG. 2. 

The ornamental design for an adjustable belt, as shown and described. 